The introduction to RSAF, in 1856, of the new machines from America, and the system of producing interchangeable components that were all identical, was a step change in the concept of engineering manufacture in the UK. Since then components have been made by precision machines to very closely controlled dimensions specified on a drawing.

Prior to that change, components were made predominantly by hand to replicate an approved pattern. It was the duty of The Board of Ordnance headed by the Master General of Ordnance to approve a master pattern for each type of weapon and to seal it by applying a hot, red wax seal, just like sealing a legal document. The sealed patterns were kept for reference in a Pattern Room at the Tower of London until 1841 when, after a disastrous fire at the Tower, the Pattern Room was transferred to the RSAF at Enfield. The Pattern Room, under Ministry of Defence ownership, then remained at RSAF until closure in 1988, albeit that it was occasionally moved between buildings as the collection grew.

The practice of applying wax seals to weapons has long since passed into history with the advent of engineering drawings but the principle remains. The Ordnance Board and the Master General of Ordnance still exist to evaluate and approve all new military weaponry and any later changes to the designs. Their approval is still signified by sealing the design though the process is now an administrative one of endorsing the master drawings, not involving any hot wax.

Though its original purpose had been overtaken by technical progress, the Pattern Room survived to become an important national reference collection of military, terrorist and other weapons, for consultation by the Armed Services, designers, researchers and Police etc. Most of the weapons are in working order though rarely fired. The collection was greatly expanded under the enthusiastic custodianship of the late Herbert Woodend MBE who could proudly boast that his Pattern Room housed the finest collection of weapons from the Warsaw Pact countries outside the Kremlin!

When RSAF closed, the Pattern Room, still under Ministry of Defence ownership, was transferred to a new specially constructed building at Royal Ordnance Nottingham. Then when Nottingham suffered the same asset-stripping fate as Enfield there was much turbulence about its future, including fears that the collection might be broken up, sold off and even pass out of the country; also that all the hand guns and machine guns, which comprise a substantial and important part of the collection, might have to be mutilated to render them inactive to comply with modern firearms legislation if the collection passed from government to civilian ownership. Fortunately that did not happen.

The Pattern Room was eventually moved to the Royal Armouries site at Leeds and in 2005 was gifted by MOD to the Royal Armouries. The Pattern Room has always been a working reference collection, NOT a museum, a point strongly emphasised by Herb Woodend. It has never been open to the general public nor is it ever likely to be so far as the weapons of current or recent operational interest are concerned, but access has always been possible, by arrangement, for people with a legitimate interest and the right credentials.

Since moving to Leeds, genuine concerns were felt that the excellent weapons collection might be split up and the historical value lost forever. However, we have now been reliably informed by the current SLA Resource Manager, Richard Jones (formerly the last Custodian), that this has not been the case and in fact the whole collection of some 20,000 examples has been maintained in its original form. The collection is housed in a private area quite separate from the public area which has on display a much more limited selection of weaponry. This really is very good news. The main change which has occurred is that the name 'Pattern Room' is now superceded and in future will be referred to by the new title 'National Firearms Centre'.